You can rest your head on a pillow, the bottom arm should be extended straight out over baby's head. I also sometimes have body ache as I side feed and cosleep with baby, but I realised it's because I just fall asleep in the same position 😅. It's better if you change into a more comfortable position after finishing feeding.
Lie sideways to the baby, with the baby head resting on your upper arm. To feed the other side, mummy can move 180 deg and repeat the same.
Lied dowm side way tgt with bb. This is very good for dream feed.
Lie down on bed and side latch.